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C. L. DREW AND Hz DE HAVEN, JR. WIRE STRETCHING- DEVICE. APPLICATION FILED NOV. 3. i920.

1,369,409. Patented Feb'.22,192 1.

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CLAYTON L. DREW AND HUGH DE HAVEN, JR., 013 SAN FRANCISCO, CALIFORNIA,

ASSIGNORS, BY ME SNE ASSIGNMENTS, TO TWISTED WIRE 80 STEEL CO., A COR- PORATION OF NEW YORK.

winn-srnn'rcnnve DEVICE.

Specificationof Letters Patent. Patented Feb 22, 1921,

Application filed November 3, 1920. Serial No. 421,582.

strand of wire to an. even tension under all conditions, and is particularly adapted for use in connection with a machine for strapping boxes, as described in our co-pending ap lication Serial Number 44108.

nother object is to produce a simple means whereby a strand of wire placed around a box will automatically be drawn to an even tension regardless of the manner in' which the opera-tor places the wire about the box.

Another obj ectis to rovide means whereby a device of this 0 aracter will operate upon boxes of different sizes and secure the same tension of wire upon all boxes, irrespective of their size.

Another object is to produce a device of this character which will prevent overstraining of the machine and consequent stretching and breaking of the wire being operated upon. I

Another object is to produce a device to manufacture and one which may be ad ed to the present machines without involving any considerable additional expense.

Other objects and advantages will be'seen as the description proceeds:

In this specification and the annexed drawings the invention is illustrated in a form consideredto be the best, but it is to be understood that the invention is not limited to said form. because it may be embodied'in other forms, and it is also to be understood that in and by the claims following the description, it is desired to cover the invention in whatsoever form it may be embodied.

In the drawings, Figure 1 is a top plan view of a wire stretching device.

Fig. 2 is a view similar to Fig. 1 with our invention applied thereto.

Fig. 3 is a diagrammatic view of a box having a strand of wire placed thereabout.

Fig. 1 is a diagrammatic view of a box of smaller size than that shown in Fig. 3 with a wire thereabout'.

Fig. 5 is a diagrammatic view illustrat ing the principle of this invention.

In strapping boxes, a strand of wire is grasped by the operator, fed to the machine and then swung about the end of the box and the free end is then threaded into the machine again, after which certain operations are performed as are described in our copending application, which tightens the wire. I

It has been found by experience that no two operators will put a wire around a box under the same tension, nor will a single operator get many wires at exactl the same tension. It has also been foundt at a wire around a large box has to be stretched farther than a wire about a small box; the reasons for this are obvious, and it is to take care of this difliculty that we have devised the inventionillustrated in this application.

In the drawings, numeral 5 deslgnates a base to which pivots 6 and 7 are attached and by referring to Fig. 1, it will be noted that we have here illustrated arms 8 and 9 attached to pivots 6 and 7. These arms are connected by a toggle formed of links 11 and 12, which toggle may be operated in any well known manner as by a handle or foot lever operating through the pusher 13.

These arms 8 and 9 are each provided with V-shaped recesses 14: and 16, which recesses serve to forma wire-engaging means. It will now be noted that if the pusher 13 is moved to its dotted position, that is so that the toggles are in their dotted position, the arms 7 and 8 will be forced a art into their dotted position and the ends of the wire 17 will have no alternative except to move with the arms, which may result in giving a proper tension, but by experience it has been found that there will either be a breaking tension or insuflicient tension.

By now referring to Fig. 2, it will be noted that arms 18 and 19 have been provided, which are similar to the arms 8 and 9, with the exception. that they are provided with elongated portions 21 and 22, having slots 23 and 21 therein. The opposite ends of these arms are formed with ll-shaped recesses 26 and 27, similar to the recesses 14- and 16. Toggle links 28 and 29 serve to connect these arms, as shown in full lines, and are operated through the medium 01" a pusher 31.

A spring tensioning means 32 is shown pivoted as at 33 and 3a to the portions 21 and 22 of thearms 18 and 19.

Assuming that a wire 36 has been placed around a box so that the ends hook over the recessed portions 26 and 27, it will be noted that if the pusher 31 is moved to its dotted position, the links 28 and 29 of the toggle will first start to force the arms 18 and 19 outwardly,"the action being the same as described in Fig. 1, the difference being, however, that when the arms 18 and 19 have been moved a distance sufiicient to take up the slack of the wire about the box, they will, as a matter of illustration, have moved to the heavy dotted line position, the arms being held against their pivot points duringthis initial movement by the tension member 32.

As soon as the tension on the wire reaches a predetermined amount the further move ment of the toggle will then cause the arms to pivot about the hooked ends of the wire and the tension number 32 will stretch a sufficient amount toallow the toggle to complete its action, at which time the arms will have been moved into the light dotted line position.

By referring to Figs. 3 and a, it will be readily seen that when stretching the wire around the box, as shown in Fig. 3, the wireengaging ends of the arms will move farther in taking up the slack than they will have moved in taking up the'slack of a wire around the box of Fig. 4:, with the result that the pivot point oi the arms will be transferred from one end to the other at a different time, but without affecting the tension upon the two boxes. This principle is well illustrated in Fig. 5, wherein the spring is illustrated by the letter A; the arms by the letters B and C the fulcrum by the letter D and the wire by the letter E, the sliding pivots by the letter F.

It pressure is brought to bear against the fulcrum D, the arms will first pivot about the pivots F until the wire finds its tension, which may be any one of the several short markings, after which the amount oi movement of the fulcrum D will serve only to stretch the spring A.

It will thus be seen that we have devised a very simple means for automatically tensioning a wire about any size case to a substantia'lly even tension, thereby eliminating the human element, a feature very desirable in work of this nature.

Having described our invention, what we desire to secure by United States Letters Patent, is:

1. In a device of the character described, a base, pivots secured to said base, arms slidably supported on said pivots, means for spreading said arms, said spreading means being spaced from said sliding support, tension means connecting said arms at a point substantially in line with said pivots, and wire-enga ing means carried at the opposite end OFSQlCl arms from said pivots.

2. In a device of the character described, wire -stretchi'ng members, wire-engaging means at one end ot' said wire-stretching members, means for forcing said members away from each other and tensioning means attached to said members at their opposite ends from said wire-engaging means. 7

3. In a device of the character described, a base, arms mounted on said base, wireengaging means carried at one end or each of said arms, means for moving said arms apart and tensioning means for limiting the spreading of said arms at their wire-engaging ends.

4. In a device of the character described, a base, arms slidably pivoted to said base, wire-engaging means carried on said arms at a point remote from said pivotal connection to said base, tensioning means between said arms at a point near their pivotal connection and means for causing said arms to move apart so as to rotate first about their pivots and then about their wire-engaging points.

5. In a device of the character described, a base, pivots securedto said base, arms supported on saidbase and adapted to slide on said pivots, means for spreading said arms apart, wire-engaging means carried at the opposite end of said arms from said pivotal connection and a resilient member attached to each of said arms near their pivots, said resilient member being adapted to limit the spreading of the wire-engaging ends of said arms.

6. In a device of the kind described, a pair of wire gripping elements, means to move said elements simultaneously in opposite directions, and other means to render the first mentioned means inoperative to move the elements whenever a predetermined tension has been placed upon the wire grip by said elements.

7 In a device of the kind described, a lever having its fulcrum yieldably supported, wire grips carried by said levers, and means a wire grip carried by the lever, and means to move said levers simultaneously in oppoto move the lever about its fulcrum and site directions. 1 10 thereby draw upon a Wire held in said wire In testimony whereof we afiix our signa- 5 grip. tures.

8. In a device of the kind described, a air CLAYTON L. DREW.

of levers; having spring connected in cm, HUGH DE HAVEN, JR. 

